Hi. I found it hard for me to solve, or even come up with an useful observation, when I'm doing a hard task. For example, yesterday in the CF round, I solved task A~E1 quickly, but I cannot solve task E2/F, though I think about task E2 for more than 1 hour. I can't even have a direction of that task. Now I can solve problems with difficulty below 2500 easily, but for the problems which are slightly harder, I have no idea to solve them. How do you think about/solve a problem with difficulty more than *2700? Also, can you tell me what did you do, and how did you train, from cannot come up with an observation to a task of *2700+, to you can solve these tasks in the competition. For the ones who have solved many red problems, I really want to know how your mind works !!!